In a general form, the present invention belongs to the technical sector of agricultural machines and equipment and refers, more specifically, to an innovative grain drying tower that uses parallel and sinuous grain flow in combination with reverse crossed air flows and radial air flow in “Z” oblique form.
Among the innumerable grain processing steps in the food industry, one of the fundamental processes is the drying of product after harvest. Drying establishes a balance between the internal humidity of the grain and the environmental humidity. This process enables that the product's high quality is maintained, avoiding at the same time that it may become susceptible to the attack of fungi and insects and, consequently, the deterioration of the grain during storage.
With this, among the equipment known in the art, drying towers have a highlighted roll, as they promote efficient drying of these grains, eliminating their humidity, and making the product less susceptible to such contaminations. Drying is, therefore, an artificial process that has the purpose of preparing the grain to be stored in a correct form avoiding losses of the product through bad storage, commercialization, and processing in the industry. The principal objective of preparing these grains through drying and humidity reduction is to maintain their physical, chemical, and biological characteristics in perfect conditions to be commercialized.
Previously, even before knowing that humidity is the cause fungi and, consequently, contamination of the stored products, grains were dried naturally. In other words, the agriculturist used to let the harvest expose product to the sun and wind in order to reduce the grains humidity. However, it is evident that such became inefficient as years went by, as this form of drying is not controlled as to provide an efficiency, and the time required by such natural drying is large, which negatively impacts the production line. Besides, the product loss during the harvest, as the grain, partially dry, possesses less weight and is more susceptible to be lost during such process.
Fixed bed dryers are known, which consist of manual dryers and of easy conception and low cost. These dryers are, generally, made in a masonry, metal boards, and have a hot air flow blown by a fan. Although presenting a low cost of acquisition, this type of solution requires that grain is dried on the metal boards, and it is necessary that an operator manually performs the movement of the grain to obtain uniform drying. From this point onward, different equipment has been developed to solve the inconvenience present in this foot industry process, reducing the time required to remove water content of the grain. From the studies and perceptions of inconvenience in the daily life, professionals of this branch have worked in developing equipment that fulfills the needs of producers in an efficient manner through practical and functional solutions.
In the present consuming market, dryers of different models and construction forms are known. The food industry trend is to supply a product that fulfills the market demands in an efficient form, allied to the reduction of operation costs and processing time. Dryers available for the treatment of grains generally are those drying towers that supply a hot air and grain flow. As seen in PI100649, a system was developed that has the purpose of integrating the grain drying and cleaning operations simultaneously. The solution foresees the cleaning system located in the superior portion of the drying system and also a heat generator. As can be seen, the solution under issue has a large inconvenience in the maintenance of the cleaning system, which demands periodic inspections in order to maintain its proper functioning. In other words, the difficulty of checking the cleaning system with greater frequency without involving larger costs and risks to the operator is evident.
Besides this, the great majority of the solutions proposed in the market presently foresee a flow of parallel grains, supplying a uniform fall. Although commonly used, this system has the inconvenience of accumulated grains placing pressure on the bottom of the tower reducing the internal space between the grains and reducing drying efficiency. As we can see in PI802885, the dryer presents itself as highly efficient for using all types of air flows possible during a process of humidity removal (concurrent, countercurrent, and crossed flow), besides varying the intensity of the flow in accordance with the characteristics presented by the grains during the process. The implementation of a flow system of radial air has the purpose of supplying a greater area of contact with the grains, however, such invention does not supply a solution for the inconvenience of supplying an efficient drying for grains and/or seeds with smaller humidity, in other words, the solution can be used with efficient results in a smaller range of grains humidity.
It is also worth mentioning the patent of the invention BR 102012001750 4, which proposes a crossed and multidirectional air flow dryer, in order to supply a low gradient of humidity. The solution foresees the parallel flow of grains resulting besides the inconvenience already mentioned: the fact of supplying larger incidence of heat for the drying of the grains of the extremities of the flow. In other words, as the grains flow is parallel, the grain disorder is small and those that are in the more internal layers of the grains flow do not receive the same incidence of heat for drying. Therefore, there is the possibility of the external grains of the grains flow column to be drier than those moving to the more inside of the grains flow column, in this way supplying a more heterogeneous product in relation to humidity.